1. The problem statement, all variables and given/known data A muon has a mass of 106MeV/c2. Calculate the speed, momentum and total energy of a 200MeV muon(a muon with a kinetic energy of 200MeV). 2. Relevant equations E=γmc K+mc2=E γ=1/(1-β)1/2 β=(v/c)2 3. The attempt at a solution To solve for the speed I plugged E=γmc into K+mc2=E to obtain K/mc2 + 1 = γ. Expanding gamma and rearranging I get 1-(K/mc2+1)-1 = β. But plugging in the numbers on the left hand side gives me a zero as K<<c2 and I think that I went wrong somewhere.